This invention relates generally to baked food products such as baked pet foods, and more particularly to coated canine biscuits, kibbles and the like. 2. Description of the Background Art
Pet foods are generally manufactured and available in dry, moist and semi-moist formulations. Moist pet foods, having a moisture content of about 50 percent or greater, are typically prepared from proteinaceous material such as meat, meat by-products or fish. Such high-moisture pet foods are usually very appealing to animals, but suffer from disadvantages including high production cost, high shipping weight and a potential for biological instability or spoilage, so that high-moisture pet foods are packaged in cans and must be consumed relatively soon after the containers are opened. Semi-moist products, which typically contain about 15 to 50 weight percent moisture, are formed from a combination of farinaceous materials, such as wheat or other grains, and proteinaceous material. These products also contain flavorings and moisture to improve palatability. However, semi-moist foods also suffer from potential biological instability, requiring sealed packaging such as sealed pouches, and such materials must also be consumed relatively soon after the container is opened.
Dry pet foods, which typically contain less than about 15 percent moisture, are formed primarily from farinaceous materials, and may contain small amounts of proteinaceous material and flavorings to improve palatability, as well as nutrients to insure a proper diet for the animal. While dry pet foods have excellent biological stability and can be packaged in bulk containers that need not be used immediately after opening, such dry pet foods also are often relatively low in palatability for the animal and low in perceived attraction to the consumer who purchases the product.
Several approaches for improving the palatability and consumer appeal of dry pet foods have been undertaken. In one, e.g., U.S. Pat. No. 3,119,691, the dry pet food is coated with gravy-forming ingredients, so that when water is added a thick gravy is formed. In another approach, a dry farinaceous core is covered with a coating of a moist proteinaceous material to mask the flavor and appearance of the core. Examples of this approach include U.S. Pat. No. 3,808,340, U.S. Pat. No. 3,615,647, British Pat. Nos. 1,389,578 and 1,465,267. Although they are attractive to consumers and the pets to which they are fed, such products also suffer from many of the disadvantages inherent in high-moisture products.
In yet another approach, as described in U.S. Pat. No. 4,229,485, a farinaceous core is covered with a coating of slurried liver, which is then dried upon the surface of the core to improve the flavor of the final product and to impart a sheen to the surface of the product, which is stated to be desirable to the consumer. In such liver-coated dry pet food products, it is then found necessary that the liver content should exceed about 50 weight percent of the coating so that the final dry product has the desired sheen. Although the liver coated dry pet food product described in U.S. Pat. No. 4,229,485 has proved successful commercially, it suffers from several disadvantages. The appearance of the product can vary from batch to batch due to variations in liver quality and minor processing variations. The relatively high liver content necessary to produce the desired sheen results in a high formulation cost, and a high production cost due to the relatively long drying times needed to reduce the moisture content of the coating to a level which will not support biological instability. Furthermore, the desirable surface sheen is obtained only with a coating containing a high proportion of liver, and not from any other possible proteinaceous ingredients. As described in such patent, the liver-containing coating is applied by immersing a hot baked biscuit in a meaty coating of farinaceous material and liver having a lower temperature, which is said to draw the coating material into the biscuit. The coated biscuit is then subjected to a second baking to form a hard crust of glazed-dried meaty substance on the exterior. U.S. Pat. No. 4,366,175 is a continuation-in-part of U.S. Pat. No. 4,229,485.
Various proteinaceous coatings and glazes are available for use on baked goods, including the glaze of U.S. Pat. No. 4,389,420, which is intended for use on refrigerated dough which is stored in containers prior to baking. The glaze contains between 4 and 25 weight percent of proteins such as gelatin, whey or casein, and has a viscosity above 10.sup.5 centipoise when measured at 5.5.degree. C.
Still another approach is taken by U.S. Pat. No. 3,808,341, which describes a food product having a core of nutritious, edible, low cost materials having textures ranging from soft and gelatinous to firm, dry and crunchy (e.g., a biscuit), this core material being covered by a coating of an edible foodstuff of substantially higher palatability than that of the core. The coating is a proteinaceous coating such as a suspension or emulsion of materials comprising egg and milk proteins. The coating serves to seal in the flavors of the core material and acts a bonding medium for securing particulate flavor bits which are applied to the exterior, the bits comprising proteins such as precooked meat, poultry or fish.
Despite the many approaches which have been taken to enhancing consumer appeal and palatability of dry pet foods, there is still an apparent need for improved dry pet food such as canine biscuits with coatings applied thereto which will combine the nutrients and tooth-cleansing effects of a dry food or biscuit with the visual appeal, flavor and nutrients available in a proteinaceous coating. In particular, processes of improved efficiency and economy for producing coated canine biscuits are desired.